Tests on seismic performance of hot-rolled stainless steel circular hollow section beam-columns

Stainless steel due to its high ductility, strain hardening, and cyclic strengthening characteristics, presents significant potential for seismic applications. The circular hollow sections (CHS) have aesthetics, stability for all axis, and low drag coefficients in wind or fluids making it common in building structures. The previous studies have shown significant differences in the behavior of stainless steel members under cyclic and monotonic loading. The studies of stainless steel CHS members have been mainly under monotonic loading, while the seismic performance under cyclic loading has not been reported. In this paper, one set of monotonic loading and five sets of quasi-static cyclic loading tests were conducted on austenitic and duplex stainless steel CHS beamcolumns, along with material properties tensile tests and laser 3D scanning initial geometric imperfection measurements. The failure modes, hysteretic responses, skeleton curves, ductility, rotational capacity, energy dissipation capacity and ultimate capacity of the stainless steel CHS beam-columns were fully obtained from the tests, which showed that stainless steel CHS beam-columns have favorable seismic performance. Evaluation of the current codes revealed a lack of accuracy in predicting cross-section classification, ductility class and ultimate capacity under cyclic loading. The reported data provide a solid reference for future validation of numerical analysis research.